Connection structure for laser and laser assembly

ABSTRACT

A connection structure for a laser and a laser assembly are provided. The connection structure for a laser includes a first insulation substrate, where the first insulation substrate includes a conductive path separately on an upper surface and a lower surface thereof. A second insulation substrate is disposed on the upper surface of the first insulation substrate. An upper surface of the second insulation substrate includes a conductive path. The conductive path on the upper surface of the second insulation substrate is electrically connected to the conductive path on the lower surface of the first insulation substrate via a through-hole. The connection structure for a laser and the laser assembly in the present disclosure are configured to supplying power to a laser.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation under 35 U.S.C. § 120 of U.S.application Ser. No. 14/944,379 filed on Nov. 18, 2015, pending, whichclaims priority of Chinese Patent Application No. 201510145308.X filedon Mar. 30, 2015, both of which are hereby incorporated by reference intheir entireties.

TECHNICAL FIELD

The present disclosure relates to the technical field of optical fibercommunications, and in particular, to a connection structure for a laserand a laser assembly.

BACKGROUND

In recent years, with a great amount of FTTH (Fiber To The Home) and3G/4G network construction in China, demands for optical devices becomegreater, and a system vendor's requirements for optical devices alsobecome higher. As a result, development of optical devices featuring ahigh rate, long-distance transmission, miniaturization and low powerconsumption has become a focus that attracts attention of equipmentvendors and device vendors.

With miniaturization development of a laser transmitter, packagingmanner thereof has changed from conventional Butterfly packaging to XMD(10 Gbit/s Miniature Device) packaging. When the number of demanded pinsis large, if the pins are all disposed at a same side surface of aceramic substrate, volume of the ceramic substrate needed for use isaccordingly increased, so that the laser transmitter occupies a greaterspace, which goes against miniaturization development of a lasertransmitter. Therefore, in the existing technology, pins are welded toopposite surfaces of a same ceramic substrate, so as to reduce volume ofthe ceramic substrate. As shown in FIG. 1, provided is a schematicdiagram of an existing laser transmitter adopting XMD packaging, whichincludes an optical fiber adapter 01, a cavity 02 and pins 03.Electrical components of the laser transmitter include a laser insidethe cavity 02 and another electrical component (not shown in thefigure). Light emitted by the laser enters an optical fiber through theoptical fiber adaptor 01. The pins 03 are welded to opposite surfaces ofa same ceramic substrate (not shown in the figure) in the cavity 02, andare connected to an external circuit for supplying power to the laserand the another electrical component.

FIG. 2 is a schematic diagram of an internal structure of the lasercavity 02 shown in FIG. 1. FIG. 3 is a schematic diagram of a ceramicsubstrate in FIG. 2. The cavity 02 includes a heat sink 04, a laser 05and a first ceramic substrate 06. A conductive layer is adhered to asurface of the heat sink 04, and a cathode of the laser 05 is laminatedon the conductive layer. The laser 05 has an anode welding spot 051 onan upper surface thereof. The first ceramic substrate 06 includes aconductive path 0A on an upper surface thereof, and a conductive path 0Bon a lower surface thereof. The conductive paths 0A and 0B arerespectively welded to pins 03 located on opposite surfaces of the firstceramic substrate 06. The anode welding spot 051 is connected to theconductive path 0A on the upper surface of the first ceramic substrate06 via a metal wire in a wire bonding manner. The pins 3 are welded tothe conductive path 0A, thereby achieving an electrical connection ofthe laser 05 and the pins 03 welded onto the conductive path 0A.

The existing manufacturing process of a laser transmitter cannot achievewire bonding in opposite directions, that is, cannot achieveestablishing an electrical connection on opposite surfaces of a ceramicsubstrate both in a wire bonding manner. However, the pins 03 are weldedto opposite surfaces of the first ceramic substrate 06, so that if anelectrical connection to a conductive path on a surface is establishedin a wire bonding manner, an electrical connection to a conductive pathon another surface cannot be established in a wire bonding manner. Forsuch a problem, a second ceramic substrate 07 is added. Referring toFIG. 2, FIG. 3 and FIG. 4, the second ceramic substrate 07 includes aconductive path 0C on an upper surface thereof. A surface where theconductive path 0B is located is laminated onto a surface where theconductive path 0C is located, so as to achieve abutting of theconductive path 0B and the conductive path 0C. Then, the conductivelayer is located at a same horizontal plane with the surface where theconductive path 0C on the second ceramic substrate 07 is located. Ametal wire is connected to the conductive path 0C of the second ceramicsubstrate 07 in a wire bonding manner. Through transferring by abuttedconductive paths, the laser 05 is electrically connected to the pins 03welded on the conductive path 0B.

However, due to a narrow conductive path and limited manufacturingprocess, as shown in FIG. 5, this transferred connection method maycauses the conductive paths 0B and 0C to be displaced during abutting,so that a relatively great error exists and consequently causes damageto impedance matching that is preset for high-frequency signals.Impedance matching is a part of microwave electronics, and is mainlyused in transmission lines, so as to achieve an objective that allhigh-frequency microwave signals can be transmitted to a load point,without any signal reflected back to an original point, therebyimproving quality of high-frequency signals. High-rate signaltransmission requires that a laser transmitter shall meet requirementsfor impedance matching demanded by high-frequency signals.

SUMMARY

Embodiments of the present disclosure provide a connection structure fora laser and a laser assembly, so as to achieve an electrical connectionof a laser and conductive paths that are distributed on an upper surfaceand a lower surface of a same substrate in a wire bonding manner, on thepremise of meeting requirements for impedance matching.

To achieve the above objective, the embodiments of the presentdisclosure adopt the following technical solutions:

A connection structure for a laser is provided, including a firstinsulation substrate, wherein the first insulation substrate includes aconductive path separately on an upper surface and a lower surfacethereof; the upper surface of the first insulation substrate includes asecond insulation substrate; an upper surface of the second insulationsubstrate includes a conductive path; and the conductive path on theupper surface of the second insulation substrate is electricallyconnected to the conductive path on the lower surface of the firstinsulation substrate via a through-hole.

In the connection structure for a laser provided by this embodiment ofthe present disclosure, to achieve connection of a laser and conductivepaths that are distributed on opposite surfaces of a same substrate in awire bonding manner, a second insulation substrate is disposed on anupper surface of a first insulation substrate, and a conductive path onan upper surface of the second insulation substrate is electricallyconnected to a conductive path on a lower surface of the firstinsulation substrate via a through-hole. During packaging, the laser cannot only be connected to a conductive path on the upper surface of thefirst insulation substrate via a metal wire in a wire bonding manner soas to achieve transmission of high-frequency signals, but also connectedto the conductive path on the upper surface of the second insulationsubstrate in a wire bonding manner. As the conductive path on the uppersurface of the second insulation substrate is connected to theconductive path on the lower surface of the first insulation substratevia a through-hole, the laser can be connected to the conductive path onthe lower surface of the first insulation substrate. Thus, the laser canbe electrically connected to conductive paths distributed on the upperand lower surfaces of a same substrate. Compared with the existingtechnology, the connection structure of the present disclosure achieves,by means of adopting a solution of transferred connection via athrough-hole, simultaneous electrical connection of a laser andconductive paths distributed on an upper surface and a lower surface ofa same substrate in a wire bonding manner. In addition, as a conductivepath on the upper surface of a first insulation substrate can bedirectly configured to transmit of high-frequency signals, a problem ofimpedance non-matching will not occur.

An embodiment of the present disclosure further provides a laserassembly, including a housing that is provided inside with a heat sink,the heat sink being provided with a laser, where the laser assemblyfurther includes a connection structure for a laser as described above;an end of the connection structure far away from the pins is insertedinto the housing; and conductive paths of the connection structure areelectrically connected to the laser in a wire bonding manner.

In the laser assembly provided by this embodiment of the presentdisclosure, to supply power to a laser and another electrical componentvia pins, a connection structure is disposed within a housing thereof.The laser is connected to a conductive path on an upper surface of afirst insulation substrate of the connection structure via a metal wirein a wire bonding manner, and is connected to a conductive path on anupper surface of a second insulation substrate in a same connectionmanner. As the conductive path on the upper surface of the secondinsulation substrate is connected to a conductive path on a lowersurface of the first insulation substrate, the laser is then connectedto the conductive path on the lower surface of the first insulationsubstrate, thereby achieving an electrical connection of the laser andall the pins. Compared with the existing technology, the connectionstructure of the present disclosure achieves, by means of adopting asolution of transferred connection via a through-hole, simultaneouselectrical connection of a laser and conductive paths distributed on anupper surface and a lower surface of a same substrate in a wire bondingmanner, and avoids using a conductive path-abutting transfer structure.Thus, pins on an upper surface of a lower substrate can be directlyconfigured to transmit of high-frequency signals, thereby solving aproblem of damage to impedance matching that is preset forhigh-frequency signals provided for the laser due to using a conductivepath-abutting transfer structure.

BRIEF DESCRIPTION OF THE DRAWINGS

To illustrate the technical solutions in the embodiments of the presentdisclosure more clearly, the following briefly introduces theaccompanying drawings required for describing the embodiments or theprior art. Apparently, the accompanying drawings in the followingdescription show merely some embodiments of the present disclosure, anda person of ordinary skill in the art may still derive other drawingsfrom these accompanying drawings without creative efforts.

FIG. 1 is a schematic view of a laser transmitter adopting XMD packagingaccording to the existing technology;

FIG. 2 is a schematic view of an internal structure of a lasertransmitter cavity in FIG. 1;

FIG. 3 is a schematic view of a ceramic substrate in FIG. 2;

FIG. 4 is a schematic view from another angle of a ceramic substrate inFIG. 2;

FIG. 5 is a sectional view of a ceramic substrate in FIG. 2;

FIG. 6 is a schematic view of a connection structure according to anembodiment of the present disclosure;

FIG. 7 is a side view of a connection structure according to anembodiment of the present disclosure;

FIG. 8 is a schematic view of connection between a first insulationsubstrate and a second insulation substrate according to an embodimentof the present disclosure;

FIG. 9 is a schematic view of a first conductive interlayer and a secondconductive interlayer disposed in a connection structure according to anembodiment of the present disclosure;

FIG. 10 is a side view of a first conductive interlayer and a secondconductive interlayer disposed in a connection structure according to anembodiment of the present disclosure;

FIG. 11 is a schematic view of a conductive path on a first insulationsubstrate according to an embodiment of the present disclosure; and

FIG. 12 is a schematic structural view of a micro-strip line in a firstinsulation substrate according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

Throughout the specification and claims, terms may have nuanced meaningssuggested or implied in context beyond an explicitly stated meaning.Likewise, the phrase “in one embodiment” as used herein does notnecessarily refer to the same embodiment and the phrase “in anotherembodiment” as used herein does not necessarily refer to a differentembodiment. It is intended, for example, that claimed subject matterinclude combinations of example embodiments in whole or in part.

In general, terminology may be understood at least in part from usage incontext. For example, terms, such as “and”, “or”, or “and/or,” as usedherein may include a variety of meanings that may depend at least inpart upon the context in which such terms are used. Typically, “or” ifused to associate a list, such as A, B or C, is intended to mean A, B,and C, here used in the inclusive sense, as well as A, B or C, here usedin the exclusive sense. In addition, the term “one or more” as usedherein, depending at least in part upon context, may be used to describeany feature, structure, or characteristic in a singular sense or may beused to describe combinations of features, structures or characteristicsin a plural sense. Similarly, terms, such as “a,” “an,” or “the,” again,may be understood to convey a singular usage or to convey a pluralusage, depending at least in part upon context. In addition, the term“based on” may be understood as not necessarily intended to convey anexclusive set of factors and may, instead, allow for existence ofadditional factors not necessarily expressly described, again, dependingat least in part on context.

Various units, circuits, or other components may be described or claimedas “configured to” perform a task or tasks. In such contexts,“configured to” is used to connote structure by indicating that theunits/circuits/components include structure (e.g., circuitry) thatperforms those task or tasks during operation. As such, theunit/circuit/component can be said to be configured to perform the taskeven when the specified unit/circuit/component is not currentlyoperational (e.g., is not on). The units/circuits/components used withthe “configured to” language include hardware—for example, circuits,memory storing program instructions executable to implement theoperation, etc. Reciting that a unit/circuit/component is “configuredto” perform one or more tasks is expressly intended not to invoke 35U.S.C. section 112, sixth paragraph, for that unit/circuit/component.Additionally, “configured to” can include generic structure (e.g.,generic circuitry) that is manipulated by software and/or firmware(e.g., an FPGA or a general-purpose processor executing software) tooperate in manner that is capable of performing the task(s) at issue.

In the description of the present disclosure, it should be understandthat positions and positional relationships indicated by the terms suchas “center”, “above”, “below”, “in front of”, “behind”, “left”, “right”,“vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside” are basedon the position or positional relationship shown in the accompanydrawings, which are used only for convenient and brief description, anddo not indicate or imply that the indicated apparatus or element must bein a specific position, and must be constructed and operated in aspecific position. In addition, in embodiments of the presentdisclosure, an inner end and an outer end are both defined according todirections of signals in a transmission path, that is, according todirections of signals in a transmission path, one end for inputtingsignals is defined as the outer end or a signal input end of thetransmission path, and another end for outputting signals is defined asthe inner end or a signal output end. Of course, other names may bedefined according to principles, and thus the foregoing cannot beunderstood as a limitation on the present disclosure.

The following clearly and completely describes the technical solutionsin the embodiments of the present disclosure with reference to theaccompanying drawings in the embodiments of the present disclosure.Apparently, the described embodiments are merely some of the embodimentsof the present disclosure rather than all of the embodiments. All otherembodiments obtained by a person of ordinary skill in the art based onthe embodiments of the present disclosure without creative efforts,shall fall within the protection scope of the present disclosure.

In the description of the present disclosure, it should be understoodthat, orientation or position relations indicted by terms such as“center”, “upper”, “lower”, “front”, “back”, “left”, “right”,“vertical”, “horizontal”, “top”, “bottom”, “internal” and “external” areorientation or position relations shown based on the accompanyingdrawings, and merely used for convenient and simple description of thepresent disclosure, but do not indicate or imply that an indicatedapparatus or element must have a specific orientation, or be constructedand operated at a specific orientation. Therefore, the orientation orposition relations shall not be understood as a limitation to thepresent disclosure.

Terms “first” and “second” are only used for the purpose of description,but cannot be understood as an indication or implication of relativeimportance, or quantity of technical characteristics that are indicated.Thus, a characteristic restricted by “first” or “second” may indicate orimply that one or more such characteristics are included. In thedescription of the present disclosure, unless otherwise stated, “aplurality of” means two or more.

In the description of the present disclosure, it should be noted that,unless otherwise explicitly specified and restricted, terms“installation”, “interconnection” and “connection” should be understoodin a broad sense. For example, it may be a fixed connection, adetachable connection, or an integral connection; it may be a mechanicalconnection, or an electrical connection; and it may be a directinterconnection, or an indirect interconnection via an intermediate, oran internal interconnection of two elements. For a person of ordinaryskill in the art, specific meaning of the foregoing terms in the presentdisclosure can be understood according to specific conditions.

In the description of the present disclosure, “outer end” refers to anend far away from a laser when a connection structure is connected tothe laser; and “inner end” refers to an end close to a laser when aconnection structure is connected to the laser.

Referring to FIG. 1, the structure of a laser transmitter adopting XMDpackaging includes an optical fiber adapter 01, a cavity 02, and pins03. Electrical components of the laser transmitter include a laserinside the cavity 02 and another electrical component (not shown in thefigure). The another electrical component generally includes amodulator, a cooler, a thermistor, a backlight detection unit, and thelike. Light emitted by the laser enters an optical fiber through theoptical fiber adaptor 01. The pins 03 are welded to opposite surfaces ofa same ceramic substrate in the cavity 02, and are connected to anexternal circuit for supplying power to the laser and the anotherelectrical component.

FIG. 6 shows a specific embodiment of a connection structure for a laseraccording to an embodiment of the present disclosure. In thisembodiment, the connection structure for a laser is mainly configured toconnect a laser to an external circuit, and supplying power to thelaser. The connection structure includes a first insulation substrate 1.The first insulation substrate 1 includes a conductive path 11 on anupper surface and a conductive path 14 on a lower surface thereof. Thelaser is connected to the conductive paths, and then the conductivepaths are connected to an external circuit, so as to achieve powersupply to the laser. Compared with a solution of disposing conductivepaths on a same surface of an insulation substrate in the existingtechnology, the conductive paths can be separately disposed on an uppersurface and a lower surface of a same insulation substrate in such amanner, thereby reducing the area of the insulation substrate and makingthe laser more miniaturized. An outer end of conductive path 11 andconductive path 14 is connected to a pin 3. Configuration of the pin 3can facilitate connecting the conductive path 11 and the conductive path14 to an external circuit. Specifically, the number of conductive paths11 on an upper surface of the first insulation substrate 1 is 5, andaccordingly, the number of pins 3 connected to the conductive paths 11on the upper surface is also 5; the number of conductive paths 11 on alower surface of the first insulation substrate 1 is 4, and accordingly,the number of pins 3 connected to the conductive paths 14 on the lowersurface is also 4. The number of conductive paths that are configuredmay be selected according to the number of components to be connected inthe laser. The upper surface of the first insulation substrate 1includes a second insulation substrate 2, so as to facilitate achievingtransferred connection of conductive paths. In addition, an uppersurface of the second insulation substrate 2 includes conductive paths21. The number of conductive paths 21 on the upper surface of the secondinsulation substrate 2 is equal to the number of conductive paths 14 onthe lower surface of the first insulation substrate 1, namely, 4, sothat the conductive paths 21 on the upper surface of the secondinsulation substrate 2 are correspondingly connected to the conductivepaths 14 on the lower surface of the first insulation substrate 1 via athrough-hole 4 a. In this way, the conductive path 14 on the lowersurface of the first insulation substrate 1 is connected to theconductive path 21 on the upper surface of the second insulationsubstrate 2. Then, an input end of the laser, an input end of themodulator, positive and negative electrodes of the cooler, thethermistor, and the backlight detection unit are respectively connectedto the conductive path 11 on the upper surface of the first insulationsubstrate 1 and conductive path 21 on the upper surface of the secondinsulation substrate 2. The pin 3 is then connected to an externalcircuit, so as to achieve power supply to the laser, the cooler andother electrical components, as well as return of thermistor signals anddetection current of the backlight detection unit.

In the connection structure for a laser provided by this embodiment ofthe present disclosure, to achieve connection of a laser and conductivepaths that are distributed on opposite surfaces of a substrate in a wirebonding manner, a second insulation substrate 2 is disposed on an uppersurface of a first insulation substrate 1, and a conductive path 21 onan upper surface of the second insulation substrate is electricallyconnected to a conductive path 14 on a lower surface of the firstinsulation substrate 1 via a through-hole 4 a. During packaging, thelaser can not only be connected to the conductive path 11 on the uppersurface of the first insulation substrate 1 via a metal wire in a wirebonding manner so as to achieve transmission of high-frequency signals,but also connected to the conductive path 21 on the upper surface of thesecond insulation substrate 2 in a wire bonding manner. As theconductive path 21 on the upper surface of the second insulationsubstrate 2 is connected to the conductive path 14 on the lower surfaceof the first insulation substrate 1 via the through-hole 4 a, the lasercan be connected to the conductive path 14 on the lower surface of thefirst insulation substrate 1. Thus, the laser can be electricallyconnected to conductive paths distributed on the upper and lowersurfaces of a same substrate. Compared with the existing technology, theconnection structure of the present disclosure achieves, by means ofadopting a solution of transferred connection via a through-hole,simultaneous electrical connection of a laser and conductive pathsdistributed on an upper surface and a lower surface of a same substrate.In addition, as a conductive path on an upper surface of a firstinsulation substrate can be directly configured to transmit ofhigh-frequency signals, a problem of impedance non-matching will notoccur.

Referring to FIG. 6, to facilitate connecting the laser to theconductive path 11 on the upper surface of the first insulationsubstrate 1 in a wire bonding manner, an end of the second insulationsubstrate 2 far away from the pin 3 includes a notch 22. The notch 22can expose an end part of the conductive path 11 on the upper surface ofthe first insulation substrate 1. Alternatively or additionally, thefirst insulation substrate 1 and the second insulation substrate 2 maybe directly disposed in a misaligned manner, so as to expose the endpart of the conductive path 11 on the upper surface of the firstinsulation substrate 1. Thus, the laser may be connected to an exposedend of the conductive path 11 on the upper surface of the firstinsulation substrate 1 in a wire bonding manner. Under a circumstancethat the substrate size is fixed, disposing two substrates in amisaligned manner may occupy more space. Therefore, the solution of FIG.6 is preferably adopted.

To achieve an electrical connection of the conductive path 21 on theupper surface of the second insulation substrate 2 and the conductivepath 14 on the lower surface of the first insulation substrate 1 via athrough-hole 4 a, and avoid the through-hole 4 being in contact with theconductive path 11 on the upper surface of the first insulationsubstrate 1, it may be configured that projection of the conductive path21 on the upper surface of the second insulation substrate 2 onto theupper surface of the first insulation substrate 1 does not overlap withthe conductive path 11 on the upper surface of the first insulationsubstrate 1. Thus, when setting the through-hole 4 a, the through-hole 4a may be prevented from contacting the conductive path 11 on the uppersurface of the first insulation substrate 1. In addition, to connect theconductive path 21 on the upper surface of the second insulationsubstrate 2 to the conductive path 14 on the lower surface of the firstinsulation substrate 1 via a vertical through-hole, projection of theconductive path 21 on the upper surface of the second insulationsubstrate 2 onto the lower surface of the first insulation substrate 1may partially overlap with the conductive path 14 on the lower surfaceof the first insulation substrate 1. In this way, the electricalconnection of the conductive path 21 on the upper surface of the secondinsulation substrate 2 and the conductive path 14 on the lower surfaceof the first insulation substrate 1 can be achieved via the verticalthrough-hole 4 a.

As connection of high-frequency signals of a laser needs to follow arule that one or one group of high-frequency signal lines (S) shall bewrapped by two ground wires (G), in FIG. 11 and FIG. 12, the conductivepath 11 on the upper surface of the first insulation substrate 1includes at least two conductive paths 11 a and 11 c configured toprovide a ground wire, and a conductive path 11 b that is configured toprovide a signal line and located between the two conductive paths 11 aand 11 c configured to provide a ground wire. The conductive path 11 bconfigured to provide a signal line is connected to an anode weldingspot of the laser for transmission of high-frequency signals on an anodeof the laser. The conductive paths 11 a and 11 c configured to provide aground wire are separately connected to a cathode of the laser. Thefirst insulation substrate 1 is provided inside with a first conductiveinterlayer 12, and the first conductive interlayer 12 is a referencelayer. The reference layer is electrically connected to the conductivepaths 11 a and 11 c configured to provide a ground wire via athrough-hole 4 b, for grounding of the cathode of the laser. Theconductive paths (11 a, 11 b, 11 c), the first conductive interlayer 12and the through-hole 4 b constitute a micro-strip line structure 7. Whenhigh-frequency signals are provided in the form of GSG as describedabove, the conductive paths 11 a and 11 c are connected to the firstconductive interlayer 12, so as to achieve grounding of the cathode ofthe laser. The conductive path 11 b is configured to transmit ofhigh-frequency signals. Because a side of the conductive paths 11 a, 11b and 11 c in the micro-strip line structure 7 is an air medium with alow dielectric constant, and another side thereof is the firstinsulation substrate 1 with a high dielectric constant, transmissionrate of high-frequency signals is improved.

In addition, when a group of high-frequency signal lines (S) are wrappedby two ground wires (G), the group of high-frequency signal lines may betwo lines with a same length and width that are close to each other,that is, constitute a differential signal line. Then, a signal line isconnected to an anode welding spot of the laser, and another signal lineis connected to a cathode of the laser, so as to transmit signals on twolines. Compared with a conventional method of a signal line and a groundwire, amplitudes of differential signals are identical, and amplitudesof coupled electromagnetic fields between the two lines and the groundwire are also identical, but signal polarities are opposite, so thatelectromagnetic fields will offset each other. In addition, interferencenoise may generally be loaded simultaneously onto two signal lines at asame intensity, and the difference is zero. Therefore, high-frequencysignals provided for the laser through differential signals can enhanceanti-interference capability of signals, and effectively inhibitelectromagnetic interference on the circuit.

Referring to FIG. 9 to FIG. 12, to ensure that electric field lines fromthe conductive path 11 b to the first conductive interlayer 12 areevenly and densely distributed, the reference layer is electricallyconnected to the conductive paths 11 a and 11 c configured to provide aground wire via a plurality of evenly distributed through-holes 4 b. Aselectric field lines near the through-holes are distributed densely, thereference layer is separately connected to the conductive path 11 a andthe conductive path 11 c via a plurality of evenly distributedthrough-holes 4 b, so that the electric field lines from the entireconductive path 11 b to the first conductive interlayer 12 aredistributed more densely and evenly.

Referring to FIG. 9 and FIG. 10, when a bottom surface of the connectionstructure is welded to a metal housing, the conductive path 14 on thelower surface of the first insulation substrate 1 is disposed near anouter end of the lower surface of the first insulation substrate 1. Thelower surface of the first insulation substrate 1 is provided near aninner end thereof with a metal layer 8 configured to weld to the laserhousing. The metal layer 8 is disposed with the conductive path 14 onthe lower surface of the first insulation substrate 1 at an interval. Asa pin 3 is welded to an outer end of the conductive path 11 on the uppersurface of the first insulation substrate 1, the second insulationsubstrate 2 shall be disposed at a relatively inner position on theupper surface of the first insulation substrate 1 to keep away from thepin 3, thereby exposing an outer end on the upper surface of the firstinsulation substrate 1. Thus, a through-hole on the second insulationsubstrate 2 is also located at a relatively inner position. In thiscase, if the through-hole directly penetrates from the upper surface ofthe second insulation substrate 2 into the lower surface of the firstinsulation substrate 1, it may easily cause the through-hole to be incontact with the metal layer 8. Therefore, to avoid occurrence of thiscase, a second conductive interlayer 13 is further provided between thefirst conductive interlayer 12 and the lower surface of the firstinsulation substrate 1. The second conductive interlayer 13 includes aplurality of conductive paths 131. The conductive paths 21 on the uppersurface of the second insulation substrate 2 respectively correspond toand are electrically connected to the conductive paths 131 of the secondconductive interlayer 13 via a through-hole 4 c. The conductive paths131 of the second conductive interlayer 13 respectively correspond toand are electrically connected to the conductive path 14 on the lowersurface of the first insulation substrate 1 via a through-hole 4 d.Then, the conductive paths 21 on the upper surface of the secondinsulation substrate 2 are connected to the conductive paths 131 of thesecond conductive interlayer 13 via the through-hole 4 c, and connectedto the conductive path 14 on the lower surface of the first insulationsubstrate 1 via the through-hole 4 d. The through-hole 4 d is more closeto the outer end of the first insulation substrate 1 compared with thethrough-hole 4 c, thereby avoiding contact with the metal layer 8.

An embodiment of the present disclosure further provides a laserassembly, including a housing (not marked in the figure). The housing isprovided inside with a heat sink 5, which is preferably an aluminumnitride heat sink. The heat sink 5 includes a laser 6, that is, of a COC(chip-on-carrier, chip-aluminum nitride heat sink) structure. Comparedwith a conventional COSOC (chip-on-submount-on-carrier, chip-small heatsink-aluminum nitride heat sink) structure of a laser, the structurereduces the number of times of welding during installation, anddecreases the thickness of vertical heat transfer. In this way, therequired cooling capacity and power consumption of the cooler arereduced. The laser assembly further includes a connection structure fora laser as described above. An end of the connection structure far awayfrom the pin 3 is inserted into the housing for the convenience ofconnection to the laser. The conductive path of the connection structureis electrically connected to the laser 6 in a metal wire bonding manner.The wire bonding refers to a technology of connecting a chip with a leadframe by using a metal wire with a wire diameter of 15 to 50micrometers, so as to make a tiny chip communicate with an externalcircuit without adding an excessively great area.

In the laser assembly provided by this embodiment of the presentdisclosure, to supply power to the laser 6 and another electricalcomponent (not marked in the figure) via the pin 3, a connectionstructure is disposed on a housing thereof. The laser 6 is connected toa conductive path 11 on an upper surface of a first insulation substrate1 of the connection structure via a metal wire in a wire bonding manner,so as to achieve transmission of high-frequency signals. The laser 6 isalso connected to a conductive path 21 on an upper surface of a secondinsulation substrate 2 in a same connection manner. As the conductivepath 21 on the upper surface of the second insulation substrate 2 isconnected to the conductive path 14 on the lower surface of the firstinsulation substrate 1 via a through-hole 4 a, the laser is connected tothe conductive path 14 on the lower surface of the first insulationsubstrate 1, thereby achieving an electrical connection of the laser 6and the conductive paths distributed on the upper and lower surfaces ofa same substrate. Compared with the existing technology, the connectionstructure of the present disclosure achieves, by means of adopting asolution of transferred connection via a through-hole, simultaneouselectrical connection of a laser and pins distributed on an uppersurface and a lower surface of a same substrate, so that a pin on anupper surface of a lower substrate can be directly configured totransmit of high-frequency signals. As use of a conductive path-abuttingtransfer structure is avoided, a problem of impedance non-matching willnot occur.

In the existing technology, a laser includes two classes, adirectly-modulated laser and an externally-modulated laser. For a commondirectly-modulated laser, such as a distributed feedback laser, thelaser can be driven only by means of providing high-frequency signals;and for a common externally-modulated laser, such as aelectro-absorption modulated laser, the laser can be driven by means ofproviding both high-frequency signals and direct current signals. Thedirect current signals are mainly configured to provide power supply toa semi-conductor cooler in an optical device, signal return of athermistor, return of detection current of a backlight detection unit,and the like. When the laser is a directly-modulated laser, theconductive path 11 on the upper surface of the first insulationsubstrate 1 is configured to transmit or receive high-frequency signals.When the laser is an externally-modulated laser, the conductive path 11on the upper surface of the first insulation substrate 1 is used partlyfor connection of high-frequency signals, and partly for connection ofdirect current signals. The conductive path on the upper surface of thesecond insulation substrate is configured to be connected to directcurrent signals.

The above descriptions are merely specific implementation manners of thepresent disclosure, but are not intended to limit the protection scopeof the present disclosure. Any change or replacement easily obtained bya person skilled in the art within the disclosed technical scope of thepresent disclosure shall fall within the protection scope of the presentdisclosure. Therefore, the protection scope of the present disclosureshall be subject to the protection scope of the claims.

What is claimed is:
 1. A device for a laser, comprising: a firstinsulation substrate, wherein: the first insulation substrate comprisesa first upper surface and a first lower surface, the first upper surfaceof the first insulation substrate comprises a first upper conductivepath, and the first lower surface of the first insulation substratecomprises a first lower conductive path; a second insulation substratedisposed on the first upper surface of the first insulation substrate,wherein: the second insulation substrate comprises a second uppersurface, and the second upper surface of the second insulation substratecomprises a second upper conductive path; a first conductive interlayeris disposed inside the first insulation substrate, wherein: the secondupper conductive path electrically connects to the first conductiveinterlayer, and the first conductive interlayer electrically connects tothe first lower conductive path; and wherein: the first lower conductivepath is disposed near a first end of the first lower surface, and ametal layer is disposed near a second end of the first lower surface,wherein: the metal layer is configured to electrically connect to anenclosure enclosing the first insulation substrate and the secondinsulation substrate, and the metal layer and the first lower conductivepath are disposed at an interval.
 2. The device according to claim 1,wherein: the second upper conductive path, via a first through-hole,electrically connects to the first conductive interlayer; and the firstconductive interlayer, via a second through-hole, electrically connectsto the first lower conductive path.
 3. The device according to claim 2,wherein: the first through-hole is disposed on top of the secondthrough-hole to form a long through-hole.
 4. The device according toclaim 2, wherein: the first through-hole is displaced from the secondthrough-hole.
 5. The device according to claim 1, wherein: a secondconductive interlayer is disposed inside the first insulation substrate;and the second conductive interlayer electrically connects to a portionof the first upper conductive path via at least one third through-hole.6. The device according to claim 5, wherein: the second conductiveinterlayer is disposed between the first conductive interlayer and thefirst upper surface.
 7. The device according to claim 5, wherein: anumber of the at least one third through-hole is larger than two; andthe at least one third through-hole distributes evenly.
 8. The deviceaccording to claim 5, wherein: the portion of the first upper conductivepath is configured to electrically connect to a ground electrode; andthe second conductive interlayer is configured to electrically connectto the ground electrode.
 9. The device according to claim 1, wherein:the second insulation substrate comprises a notch on an end part of thesecond insulation substrate; and the notch exposes an end part of thefirst upper conductive path.
 10. The device according to claim 1,wherein: the second insulation substrate covers a portion of the firstupper surface of the first insulation substrate to expose an end part ofthe first upper conductive path.
 11. The device according to claim 1,wherein: projection of the second upper conductive path onto the firstupper surface of the first insulation substrate partly overlaps with thefirst upper conductive path.
 12. The device according to claim 1,wherein: projection of the second upper conductive path onto the firstupper surface of the first insulation substrate does not overlap withthe first upper conductive path.
 13. The device according to claim 1,wherein: projection of the second upper conductive path onto the firstlower surface of the first insulation substrate partly overlaps with thefirst lower conductive path.
 14. A laser assembly, comprising: anenclosure enclosing a laser and a device, the device comprising: a firstinsulation substrate, wherein: the first insulation substrate comprisesa first upper surface and a first lower surface, the first upper surfaceof the first insulation substrate comprises a first upper conductivepath, and the first lower surface of the first insulation substratecomprises a first lower conductive path; a second insulation substratedisposed on the first upper surface of the first insulation substrate,wherein: the second insulation substrate comprises a second uppersurface, and the second upper surface of the second insulation substratecomprises a second upper conductive path; a first conductive interlayeris disposed inside the first insulation substrate, wherein: the secondupper conductive path electrically connects to the first conductiveinterlayer via a first through-hole, and the first conductive interlayerelectrically connects to the first lower conductive path via a secondthrough-hole; and wherein: a second conductive interlayer is disposedinside the first insulation substrate, and the second conductiveinterlayer electrically connects to a portion of the first upperconductive path via at least one third through-hole.
 15. The laserassembly according to claim 14, wherein: a portion of the first upperconductive path electrically connects to the laser in a wire bondingmanner; and a portion of the second upper conductive path electricallyconnects to the laser in the wire bonding manner.
 16. The laser assemblyaccording to claim 15, wherein: a portion of the first upper conductivepath electrically connects to the laser in the wire bonding manner forconnection of high-frequency signals; and a portion of the second upperconductive path on the second upper surface of the second insulationsubstrate electrically connects to the laser in the wire bonding mannerfor connection of direct current signals.
 17. The laser assemblyaccording to claim 15, wherein: a metal wire used in the wire bondingmanner has a diameter between 15 micrometers and 50 micrometers.
 18. Thelaser assembly according to claim 14, further comprising: a modulatordisposed in the enclosure; a thermistor disposed in the enclosure; and abacklight detection unit disposed in the enclosure.